Ultra-thin fabric, devices, and methods

ABSTRACT

A fabric can comprise yarns comprising less than about 30 denier total and less than about 10 denier per filament; a density of greater than about 177 yarns per cm 2 ; and a thickness of less than about 3.2 mil. The fabric can further comprises a weight of less than about 60 g/m 2 . The fabric can have performance characteristics equivalent to or greater than those in conventional implantable fabrics. A method of making such a fabric can include twisting together filaments into a multifilament yarn; passing adjacent yarns into a loom in parallel so as to allow the yarns to be woven together more closely; maintaining a consistent tension on the yarns during placement of the yarns on a loom beam and during weaving; and or subjecting the fabric to increased heat and pressure so as to compress the yarns more tightly.

CROSS-REFERENCE TO RELATED APPLICATION APPLICATIONS

This application is a reissue continuation application, meaning it is acontinuation of Reissue application Ser. No. 15/378,268, filed Dec. 14,2016, and is also a reissue of U.S. Pat. No. 9,876,543, granted Dec. 16,2014, which claims the benefit of U.S. Provisional Patent App. No.61/287,989, filed Dec. 18, 2009, which application is incorporated byreference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to an ultra-thin, high density, low denierfabric, devices including ultra-thin, high density, low denier fabric,and methods for making an ultra-thin, high density, low denier fabric.

BACKGROUND

Medical devices such as vascular and endovascular grafts andstent-grafts can include fabric components that provide variousfunctions. For example, the fabric component of an endovascular devicecan function to promote sealing of the device to the lumen or structurein which it is implanted. Insertion of such devices and fabriccomponents into target sites can require that the device and fabriccomponent be passed through the lumen of a delivery catheter or cannula.

Conventional fabrics used for implantable medical devices generallyutilize yarns having a linear density of about 40 denier or higher. Asan example, a cardiovascular implant usable as a heart valve or forvessel repair can have a graft material about the perimeter of theimplant that comprises 40 denier yarns. Implantable devices that includegrafts having yarn densities in this range can typically be deliveredthrough a 16-22 French catheter or higher on the French catheter scale.The French catheter scale (abbreviated as Fr) is commonly used tomeasure the outer diameter of cylindrical medical instruments includingcatheters. In the French system, the diameter in millimeters of thecatheter can be determined by dividing the French size by 3. Thus, adecreasing French size corresponds with a smaller diameter catheter.

In certain medical circumstances, it may be desirable to use a smallerouter diameter catheter to deliver an implantable device. For example,it may be desirable to use a smaller diameter catheter in a patienthaving a smaller anatomical area through which a surgical site isaccessed, such as by percutaneous means, or in a patient in which theanatomical location of repair is smaller than average. In order toutilize smaller diameter delivery catheters, the implantable devicesdelivered through such catheters need to be smaller as well. Inparticular, smaller diameter delivery catheters may require implantabledevices having a smaller diameter.

Thus, there is a need for an ultra-thin fabric that can allow animplantable device to have a smaller overall diameter, therebypermitting the device to be delivered through a smaller diametercatheter. There is a need for such a fabric that can exhibit performancecharacteristics similar to those of thicker implantable fabrics.

SUMMARY

The present invention includes embodiments of an ultra-thin, highdensity, low denier fabric, devices including ultra-thin, high density,low denier fabric, and methods for making an ultra-thin, high density,low denier fabric.

In an illustrative embodiment, such a fabric can comprise yarnscomprising less than about 30 denier total and less than about 10 denierper filament; a density of greater than about 177 yarns per cm²; and athickness of less than about 3.2 mil. The fabric can further comprisescomprise a weight of less than about 60 g/m². In some embodiments, thefabric can further comprises comprise an implantable medical device. Incertain embodiments, the implantable medical device is passable througha small introduction catheter usable for percutaneous insertion, forexample, a 10 French or less delivery catheter. In some embodiments, theyarns can comprise multifilament yarns, and each yarn can include 10filaments and a total denier of about 20. The yarns may comprisepolyester, polypropylene, polytetrafluoroethylene, nylon, and/orpolyethylene yarns. Some embodiments of the fabric can comprise a waterpermeability rating of less than about 400 cc/min/cm² at 120 mm Hgpressure. Some embodiments of the fabric can comprise a probe burststrength of greater than about 20 lbs. Some embodiments of the fabriccan comprise a tensile strength of greater than about 25 lbs. per inch.

Some embodiments of the present invention can include a method of makingthe ultra-thin, high density, low denier fabric and/or devices includingthe ultra-thin, high density, low denier fabric. Such a method caninclude fabricating a fabric comprising yarns comprising less than about30 denier total and less than about 10 denier per filament, a density ofgreater than about 177 yarns per cm², and a thickness of less than about3.2 mil; and slashing the yarns with a protective coating prior tofabricating the fabric. The yarns can comprise multifilament yarns, andthe method can further comprise twisting the filaments together. Someembodiments of the method can further comprise passing adjacent yarnsinto a loom in parallel so as to allow the yarns to be woven togethermore closely. Some embodiments of the method can further comprisemaintaining a consistent tension on the yarns during placement of theyarns on a loom beam and during weaving. Some embodiments of the methodcan further comprise subjecting the fabric to increased heat andpressure so as to compress the yarns more tightly.

Features of a fabric, device, and/or method of the present invention maybe accomplished singularly, or in combination, in one or more of theembodiments of the present invention. As will be realized by those ofskill in the art, many different embodiments of a fabric, device, and/ormethod according to the present invention are possible. Additional uses,advantages, and features of the invention are set forth in theillustrative embodiments discussed in the detailed description hereinand will become more apparent to those skilled in the art uponexamination of the following.

DETAILED DESCRIPTION

For the purposes of this specification, unless otherwise indicated, allnumbers expressing quantities, conditions, and so forth used in thespecification are to be understood as being modified in all instances bythe term “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification areapproximations that can vary depending upon the desired propertiessought to be obtained by the embodiments described herein. At the veryleast, and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldat least be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the described embodiments are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard deviation foundin their respective testing measurements. Moreover, all ranges disclosedherein are to be understood to encompass any and all subranges subsumedtherein. For example, a stated range of “1 to 10” should be consideredto include any and all subranges between (and inclusive of) the minimumvalue of 1 and the maximum value of 10; that is, all subranges beginningwith a minimum value of 1 or more, e.g. 1 to 6.1, and ending with amaximum value of 10 or less, for example, 5.5 to 10. Additionally, anyreference referred to as being “incorporated herein” is to be understoodas being incorporated in its entirety.

As used in this specification and the appended claims, the singularforms “a,” “an,” and “the” include plural referents unless the contextclearly dictates otherwise. Thus, for example, the term “a yarn” isintended to mean a single yarn or more than one yarn. For the purposesof this specification, terms such as “forward,” “rearward,” “front,”“back,” “right,” “left,” “upwardly,” “downwardly,” and the like arewords of convenience and are not to be construed as limiting terms.

The present invention can include embodiments of an ultra-thin, highdensity, low denier fabric, devices including ultra-thin, high density,low denier fabric, and methods for making an ultra-thin, high density,low denier fabric.

In an illustrative embodiment, the ultra-thin, high density, low denierfabric can comprise a fabric (“wall”) thickness of less than about 3.2mil. A mil is a unit of length, in which 1 mil is equal to 0.001 inch.In some preferred embodiments, the fabric wall thickness can be about4.0 mil. Conventional fabrics utilized in implantable medical deviceapplications can typically have a thickness of about 4.3 mil to about5.5 mil or greater. Thus, embodiments of the fabric of the presentinvention can be thinner than conventional implantable fabrics.

In some applications, for example, in a cardiovascular implant, thegraft fabric can comprise the majority of the diameter of the implantdevice in a collapsed package for delivery through a delivery catheter.Embodiments of the ultra-thin fabric of the present invention candecrease the profile, or cross-sectional diameter, of an implantablemedical device incorporating the fabric. Thus, such an ultra-thin fabricwall thickness can minimize the packing volume, and thus the capsulesize, of the device so that the device can be introduced through smallersized catheters. For example, an implantable device comprising theultra-thin fabric having a fabric wall thickness of about 4 mil or lesscan be passed through delivery catheters having a size of about 10.Accordingly, as compared to a conventional implantable fabric,embodiments of the ultra-thin fabric of the present invention canprovide the advantage of a smaller diameter device package that can bedelivered through a smaller diameter catheter. Such an ultra-thin fabricwall thickness can be useful in providing implantable devices utilizedin percutaneous and/or minimally invasive surgical applications.

In certain applications, for example, in which the ultra-thin, highdensity, low denier fabric comprises at least a portion of animplantable device, the device can be passed through a catheter havingthe same, or smaller, diameter than previously used.

In some embodiments, the ultra-thin fabric can comprise a higher densityof yarns than conventional implantable medical fabrics. By utilizingmore yarn per square meter in the ultra-thin fabric, the fabric densitycan be increased. For example, some embodiments of the fabric cancomprise 177 yarns per cm². In certain embodiments, an increased amountof warp yarns, or ends, can be used to increase fabric density. In otherembodiments, an increased amount of filling yarns, or picks, can be usedto increase fabric density. In still other embodiments, an increasedamount of both warp ends and filling picks are used to increase fabricdensity. Preferably, at least an increased amount of warp ends are usedto increase fabric density. Utilizing lower denier yarns allows thefabric to be constructed with such an increased density, that is, adensity that is higher than in conventional implantable medical fabrics.

However, due to the use of lower denier yarns, although the density ofthe ultra-thin fabric can be higher than in conventional implantablemedical fabrics, the ultra-thin fabric can comprise a lower weight thanconventional implantable medical fabrics. In some embodiments, theultra-thin fabric can comprise a weight of less than about 60 g/m². Forexample, in preferred embodiments, the ultra-thin fabric can comprise aweight in the range of about 40 g/m² to about 58 g/m². In contrast,conventional implantable medical fabrics can often have a weight ofgreater than about 60 g/m², for example, between about 60 g/m² and about120 g/m².

In some embodiments, the ultra-thin fabric can comprise yarns having anaverage linear density of less than about 30 denier total and less thanabout 10 denier per filament. As a result, a denser, or more tightlyconstructed, fabric can be fabricated. Such a denier is lower than inyarns in typical conventional implantable medical fabrics. Thus,fabric-incorporating devices having a smaller diameter can be producedsuch that the device can be delivered through a smaller diametercatheter, or other tubular structure. In addition, some embodiments ofthe ultra-thin, high density, low denier fabric can be as fluid tight asfabrics comprising higher denier yarns.

In some embodiments of the high density low denier fabric, the fabriccan be fabricated by weaving, by knitting, and/or by non-wovenprocesses. Some embodiments of the fabric can be a tubular fabric or aflat fabric.

Yarns useful for some embodiments of the high density low denier fabricinclude, for example, polyester, polypropylene, polytetrafluoroethylene(PTFE), nylon, and/or polyethylene yarns. Other yarns appropriate forimplantable medical devices and that provide desired characteristics atlow deniers may be utilized. In some preferred embodiments, the yarnsutilized in the ultra-thin, high density, low denier fabric can bemultifilament yarns. In other embodiments, the yarns can be monofilamentyarns.

An implantable medical fabric that is ultra-thin and has low denieryarns can be difficult to fabricate. This is because thinner, low denieryarns can have less strength and abrasion resistance and thus besusceptible to breakage due to the stresses and strains during weaving,knitting, or other construction. Therefore, in some embodiments of thepresent invention, certain preparation and/or management of the yarn canhelp protect the yarn from such stresses and strains during manufacture.

For example, in some embodiments, the ultra-thin fabric of the presentinvention can comprise yarns that have undergone “slashing” prior tofabrication into the fabric. For purposes herein, “slashing” is definedas a process of sizing, or coating, yarns to protect the yarns againstinjury during weaving, knitting, or other construction such as duringmanufacture of a non-woven fabric. Such protection provides temporarystrength and abrasion resistance to the yarns to enable them to resistthe stresses and strains in, for example, the loom or knitting machine.In one embodiment, the yarns can be coated by immersion in the sizingmaterial and then dried before use in the loom or knitting machine.Certain preferred sizing materials can provide enhanced protection tothe yarns during weaving, knitting, or other construction.

In some embodiments, the ultra-thin fabric of the present invention cancomprise yarns that have undergone “twisting” of individual filaments tomake the yarn. For purposes herein, “twisting” is defined as a processof twisting an individual yarn, or combining two or more parallelsingles or ply yarns by twisting together to produce a plied yarn orcord. Twisting is employed to obtain greater strength and smoothness,and increased uniformity. For example, an illustrative yarn useful forfabricating embodiments of the ultra-thin fabric can include tenfilaments twisted together to make the yarn. That is, such a yarn caninclude ten filaments, and the total linear density of the 10-filament,twisted yarn can be about 20 denier.

In some embodiments of the ultra-thin fabric of the present invention,the flow of yarns into a loom can be controlled so as to enter the loomin parallel fashion. For example, during the process of “warping,” inwhich yarns from individual packages of yarn are placed on a beam,multiple warp ends can be moved parallel to one another onto the beamfor routing into the loom. Controlling movement of the yarns into theloom in such a manner can allow the yarns to be woven more closelytogether, thereby creating a denser fabric.

In some embodiments of the ultra-thin fabric of the present invention,tension on the yarn can be controlled so as to provide a consistenttension on the yarn during preparation of the yarn and/or duringfabrication of the fabric. That is, yarn tension can be controlled bothduring “warping” and during weaving. In this way, the stresses andstrains on the low denier yarns can be minimized, thereby protecting theyarn during preparation and manufacture of the ultra-thin fabric. Inaddition, providing a controlled, consistent tension on the yarn allowsfabrication of a denser fabric.

Once an embodiment of the ultra-thin fabric has been fabricated, thefabric can be utilized in the formation of an implantable medicaldevice. During formation of such a device, the ultra-thin fabric can besubjected to increased heat and/or pressure in a controlled manner. Suchincreased heat and/or pressure can compress the low denier fibers moretightly and achieve an even higher density fabric.

Such yarn preparations, management of the yarn during preparation andfabrication of the ultra-thin fabric, and controlled formation of thefabric into a device can be performed in weaving, knitting, and/or otherprocesses. Various combinations of these and other steps can be taken tohelp provide a strong, flexible, and compactable ultra-thin fabric.

Some embodiments of the ultra-thin, high density, low denier fabric ofthe present invention can exhibit performance characteristics similar toconventional lower density fabrics having higher denier yarns.

For example, in some embodiments, the ultra-thin, high density, lowdenier fabric can comprise a water permeability rating of less thanabout 400 cc/min/cm² at 120 mm Hg pressure.

In some embodiments, the ultra-thin, high density, low denier fabric cancomprise a probe burst strength of greater than about 20 lbs. Probeburst strength can be determined by pressing a probe into a one inchdiameter portion of fabric and measuring the force at which the probebursts through the fabric (in accordance with ISO 7198). Conventionalimplantable medical fabrics can often have a probe burst strength ofabout 20 lbs. or greater.

In some embodiments, the ultra-thin, high density, low denier fabric cancomprise a tensile, or longitudinal, strength of greater than about 25lbs. per inch.

Some embodiments of the present invention can include a method of makingthe ultra-thin, high density, low denier fabric and/or devices includingthe ultra-thin, high density, low denier fabric. Such a method caninclude fabricating a fabric comprising yarns comprising less than about30 denier total and less than about 10 denier per filament, a density ofgreater than about 177 yarns per cm², and a thickness of less than about3.2 mil; and slashing the yarns with a protective coating prior tofabricating the fabric. The yarns can comprise multifilament yarns, andthe method can further comprise twisting the filaments together. Someembodiments of the method can further comprise passing adjacent yarnsinto a loom in parallel so as to allow the yarns to be woven togethermore closely. Some embodiments of the method can further comprisemaintaining a consistent tension on the yarns during placement of theyarns on a loom beam and during weaving. Some embodiments of the methodcan further comprise subjecting the fabric to increased heat andpressure so as to compress the yarns more tightly.

Some embodiments of an ultra-thin, high density, low denier fabricaccording to the present invention may be utilized in implantablemedical devices. For example, such ultra-thin fabrics may be utilized incardiovascular applications, including heart valves and stent-grafts,spinal applications, cosmetic surgery, and/or general surgery. In someapplications, such ultra-thin fabrics may be utilized as a barriersheath in a prosthetic material. In other applications, such ultra-thinfabrics may be utilized as reinforcement material adapted for repairinga prosthetic graft. Certain embodiments of the implantable medicalfabric according to the present invention may be utilized in any devicesuitable for endovascular implantation. Embodiments of such ultra-thin,high density, low denier fabric may be utilized in applications otherthan medical. For example, such ultra-thin fabrics may be utilized inindustrial, aeronautics, telecommunications, research, and/or otherapplications in which a device having a fabric component is passedthrough, or placed in, a small diameter tubular structure and/or inwhich it is desirable for the device to have performance characteristicssimilar to those incorporating lower density and/or higher denierfabrics.

Although the present invention has been described with reference toparticular embodiments, it should be recognized that these embodimentsare merely illustrative of the principles of the present invention.Those of ordinary skill in the art will appreciate that an ultra-thin,high density, low denier fabric, device, and methods of the presentinvention may be constructed and implemented in other ways andembodiments. Accordingly, the description herein should not be read aslimiting the present invention, as other embodiments also fall withinthe scope of the present invention.

What is claimed is:
 1. A fabric, comprising: yarns, comprising more than1 and less than about 30 denier total and more than 0.1 and less thanabout 10 denier per filament; a density of greater than about 177 yarnsper cm²; and a thickness of less than about 3.2 mil; wherein the fabricfurther comprises a water permeability rating of less than about 400cc/min/cm² at 120 mm Hg pressure.
 2. The fabric of claim 1, wherein thefabric further comprises a weight of less than about 60 g/m².
 3. Thefabric of claim 1, wherein the fabric further comprises an implantablemedical device.
 4. The fabric of claim 3, wherein the implantablemedical device is passable through a size 10 French delivery catheter.5. The fabric of claim 1, wherein the yarns comprise multifilamentyarns, each yarn having 10 filaments and a total denier of about
 20. 6.The fabric of claim 1, wherein the yarns comprise polyester,polypropylene, polytetrafluoroethylene, nylon, and/or polyethyleneyarns.
 7. The fabric of claim 1, wherein the fabric further comprises aprobe burst strength of greater than about 20 lbs.
 8. The fabric ofclaim 1, wherein the fabric further comprises a tensile strength ofgreater than about 25 lbs. per inch.
 9. A method, comprising:fabricating a fabric comprising less than about 30 denier total and lessthan about 10 denier per filament, a density of greater than about 177yarns per cm², and a thickness of less than about 3.2 mil, wherein thefabric further comprises a water permeability rating of less than about400 cc/min/cm² at 120 mm Hg pressure; and slashing the yarns with aprotective coating prior to fabricating the fabric.
 10. The method ofclaim 9, the yarns comprising multifilament yarns, the method furthercomprising twisting the filaments together.
 11. The method of claim 9,further comprising passing adjacent yarns into a loom in parallel so asto allow the yarns to be woven together more closely.
 12. The method ofclaim 9, further comprising maintaining a consistent tension on theyarns during placement of the yarns on a loom beam during weaving. 13.The method of claim 9, further comprising subjecting the fabric toincreased heat and pressure so as to compress the yarns more tightly.14. A fabric comprising: yarns comprised of the group consistingessentially of polyester, nylon, polypropylene, polyethylene, andpolytetrafluoroethylene, the yarns comprising less than about 30 deniertotal and less than about 10 denier filament; a density of greater thanabout 177 yarns per cm²; and a thickness of less than about 3.2 mil;wherein the fabric further comprises a water permeability rating of lessthat about 400 cc/min/cm² at 120 mm Hg pressure.
 15. The fabric of claim14, wherein the fabric further comprises a weight of less than about 60g/m².
 16. The fabric of claim 14, wherein the fabric further comprisesan implantable medical device.
 17. The fabric of claim 16, wherein theimplantable medical device is passable through a size 10 French deliverycatheter.
 18. The fabric of claim 14, wherein the fabric furthercomprises a probe burst strength of greater than about 20 lbs.
 19. Thefabric of claim 14, wherein the fabric further comprises a tensilestrength of greater than about 25 lbs. per inch.
 20. An implantablemedical fabric having a desired fabric construction, comprising: afabric thickness of less than about 3.2 mil; a water permeability ratingof less than about 400 cc/min/cm² at 120 mm Hg pressure; and yarnshaving filaments, wherein the yarns have a total denier of less thanabout 30 denier and the filaments have a denier per filament of lessthan about 10; wherein said fabric comprises a tensile strength ofgreater than about 25 lbs. per inch.
 21. The implantable medical fabricof claim 20, further comprising a fabric weight of less than about 60g/m².
 22. The implantable medical fabric of claim 21, wherein the fabricweight is from about 40 g/m² to about 58 g/m².
 23. The implantablemedical fabric of claim 20, wherein the yarns are woven to form saidfabric.
 24. The implantable medical fabric of claim 20, wherein saidfabric is a tubular fabric.
 25. The implantable medical fabric of claim20, wherein said fabric is a flat fabric.
 26. An endovascular devicecomprising the implantable medical fabric of claim
 20. 27. Theendovascular device of claim 26, wherein said endovascular device is astent-graft.
 28. An endovascular device comprising the implantablemedical fabric of claim 20, wherein said device is selected from thegroup consisting of a heart valve, a barrier sheath in a prostheticmaterial, and a reinforcement material adapted for repairing aprosthetic graft.
 29. The implantable medical fabric of claim 20,wherein said fabric may be utilized in cardiovascular applications,spinal applications, cosmetic surgery, and general surgery.
 30. Theimplantable medical fabric of claim 20, wherein said yarns aremultifilament yarns.
 31. The implantable medical fabric of claim 30,wherein said filaments are twisted to form said multifilament yarns. 32.A method of making a medical fabric having a desired fabric constructioncomprising: selecting yarns having a total denier less than about 30denier and having a denier per filament of less than about 10;fabricating the medical fabric from said yarns, wherein said fabriccomprises a fabric thickness of less than about 3.2 mil, a tensilestrength of greater than about 25 lbs. per inch, and a waterpermeability rating of less than about 400 cc/min/cm2 at 120 mm Hgpressure.
 33. The method of claim 32, further comprising fabricating themedical fabric with a fabric weight of less than about 60 g/m2.
 34. Themethod of claim 33, wherein the fabric weight is from about 40 g/m2 toabout 58 g/m2.
 35. The method of claim 32, further comprising twistingthe filaments together to form said yarns.
 36. The method of claim 32,further comprising passing adjacent yarns into a loom in parallel. 37.The method of claim 32, further comprising maintaining a tension on theyarns during placement of the yarns on a loom beam and during weaving.38. The method of claim 32, further comprising compressing the yarns.39. The method of claim 32, further comprising slashing the yarns with aprotective coating prior to fabricating the medical fabric.
 40. Animplantable medical fabric having a desired fabric construction,comprising: a fabric thickness of less than about 3.2 mil; a waterpermeability rating of less than about 400 cc/min/cm² at 120 mm Hgpressure; a fabric weight of less than about 60 g/m²; and yarns havingfilaments, wherein the yarns have a total denier of less than about 30denier and the filaments have a denier per filament of less than about10.